Shock absorber



I UNITED stra s Patented Oct. 11, 1932 SHOCK ABsoRBER Application filedFebruary 10, 1930. Serial No. 427,107i

This invention relates to a shock absorber which is more particularlyintended for use on automobiles although the same may also tion and theresistance in this type of shock absorber is governed by the size of .1l1qu1d passages, clearances between parts and valve openings which aredesigned to allow the liquid to pass from a high to a lower pressurechamber at a predetermined rate; It is a property of the liquid used inthis type of shock absorbers that it is very slightly compressed bypressure in resisting the movements of the pistons, whereas if air orgases are subjected to this pressure they will be compressed arelatively large amount.

Thus, if air or gases are allowed to remain in the working chambers theres1stance of the shock absorber will be less than required and itsusefulness impaired. 30

The object of this invention is to provide means whereby due to theaction of the shock absorben. air or gases will be discharged from v theworking chambers during high pressure strokes of the piston or when thepressure is higher than-in the replenishing chamber but which willprevent the same from returning or re-entering the working chamber whenthe pressure in the workingchamber has been reduced or becomes less thanthat in the replenishing chamber.

In the accompanylng drawing: Figure 1 is a vertical 'longltudlnalsect1on of one form of hydraulic shock absorber containing oneembodiment of my invention.

Figure 2 is a vertical transverse section of the same taken on line 2-2Fig. 1.

Figure 3 is a fragmentary vertical section, on an enlarged scale, of thevent filtering ineans shown in Fig. 1.

present case is wall 10 Which is adapted to be connected Figure 4 is asimilar View of a modified form of the vent filtering means. f 5

Figure 5 is an end viewof the vent plug shown in Figs. 1, 3 and 4. 7

Figures 6 and 7 are similar viewsshowing' modified forms of the ventplug. V v

Figure 8 is a fragmentary horizontal section of the workingandreplenishing chambers, thepartition, between, the working chambers andthe venting and filtering means communicating with the several chambers.

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RALPH r. PEO, or KENMORE, NEW YORK,'ASSIGNOR '10 HO'UDENGiNEERINe-coRroRA- TION, or BUFFALO, NEW YORK, A CORPORATION or NEWYORK r e I Figure 9 is a fragmentary section showing a modified form ofvent passage on the retaining plug. 7 Y 1 s In the following descriptionsimilarlcharacters of reference indicate like parts in the severalfigures of the drawing.

This invention is applicable to'hydraulic i shock absorbers and dampingand cushioning devices of various types regardless of whether theplstons reciprocate lengthwise in a cylinder or oscillatecircumferentially in a segmental working chamber and it is exceptasdefined by the appended claims.

The shock absorber which is shown in the use in connection with thisstructed as follows r V y The body of the shock absorber in the providedwith a' cylindrical.

therefore to be understood that this invenj tion is not confined to anyparticular form with the frame of theautomobile by bolts passing throughlugs 11 on opposite sides of this wall. At its inner or rear end thespace within the wall 10 is closed by a rear head 12 which is preferablyformed integral therewith and at its front end this space is closed by atransverse front head or wall 13 whichis connected with the circularwall by a screw joint 14 and provided centrally with a forwardlyprojecting bearing 15.

The cylindrical space within the circular'wall and front and rear headsof'the body is divided into two segmental working chambers. 16, 17 by adiametrical partition composed of upper and lower sections 18, 19.Within? the working chambers two pistons 20, 21 cs cillatev back andforth,these pistons being 7 formed on opposite sides of a hub 22 whichhas a rock shaft 23 journaled in the bearing and connected externally ofthe absorber by a rock arm 9 or any other suitable means or with an axleof the automobile so that when the spring between the frame and axle iscompressed the pistons, will be moved back- Wardly in the workingchambers with a low pressure stroke toward the low pressure ends ofthe/"Working chambers, and when the frame and axle of the car, separateduring rebound of the spring means he pistons will be moved toward thehigh pressure ends ofthe working chambers- The arrow associated with thepistons in Fig 2 indicates thedirection which the same move when makinga bound stroke,it being understood thatwhen the pistons move in adirection opposite to the arrow that thesame are'elfecting a low-pressu're stroke. Each of the partitions or sections 18, 19 containsaport 2t controlled by a check'v'alve 25 whereby during low pressurestroke the resistance'liquid can flow from the'upper'low pressure end ofthe right worki'ngflchamber 17 to the upper high presv sure end of theleft working chamber 16, and

from the lower low pressure end of the left working chamber 16 to thelower h1ghpres= sure end ofthe right working chamber, but

during areversed movement of the pistons these check valves are closedand prevent the flow, of resistance liquid throughthe partition sectionsso that a greater resistance is offered to the movement of the pistonsduring the high pressure strokes than during the low pressure strokes. r

In order to permit of regulating the liquid resistance to the movementof the pistons adjustable by-pass means are provided for v the flow ofthe liquid which inthe present case consist of bypass ports 26, 27formed on thehub of the pistonsvand leading from H opposite sides of thepistons to point ar-,

ranged in front and in rear of a valve seat 28 within the axis of thepiston hub, and a regulating valve stem 29 adjustable lengthwise, inthe'rock shaft by means of a screw joint 30 and provided at its innerend with avalve 81 movable toward and from the valve seat and providedat its outer end with a handle 32 for adjusting this valve stem andcapacity of the by-pass. Upon opening the bypass more or less theresistance liquid is free to flow to a limited extent back and, forthbetween the high and low pressure sides of the pistons and-therebypermits of adapting the capacity of the absorber to the load which isbeing carried.

In front, of

the working chambers is archambers as, required. This liquid isintroduced into the replenishingchamber through] high pressure or re-rgreater and diminished or made less than' that 1n the replenishingchamber. As a result the replenishing valve means allows a smallquantity ofthe resistance liquid to be drawn into the lower ends of theworking chambersduring each low pressure stroke of r the pistons.v Thereis thus a tendency for liquid and air or gas, ifthere is any in theworking chambers, to flow outward from the upper ends of the workingchambers to the replenishing chamber.

1 Due to the change 1n pressure in the work- 7 ing chambers there isalso a tendency for vent passage from the replenishing chamber to'theworking chambers during the low presliquid and air or gas to returnthrough the sure strokes ofthe pistons.v

The vent valve devices heretorore employed 7 have. not been entirelysatisfactory to over-,-

come this difiiculty inasmuch as the same permitted air to pass from thereplenishing chamber back to the working chambers, have wasted an undueamount of resistance liquid from the workingchamber :to the replenisli'lng chamber,-or have become clogged by the obstructing effectproduced bysmall particles of foreign matterfpresent inr the resistance liquid. 7

In these prior vent valve means the vent passage was restricted and ofrelatively small cross sectional area compared to its length andextended between'the working and reand entrained air or gas would floweither from theworking chambers to, the IGPlQIllSlhing chamber, or fromthe replenishing chamimpair the efficiency of the instrument.

The present invention provides improved venting means whereby a1r andliqu d are conducted from the upper ends of one or both 'workingchambers to the replenishing chamber without permitting any foreignmatter to obstruct thevent passages. and Without permitting any reverseflow of air from the replenishing chamber through the vent passage tothe working chambers. r If desiredtwo venting means embodying thisimprovement may be embodied in the shockabsorber, one of which connectsthe plenishing chambers in such a way that liquid vices shown in Figs.1, 2, 8 and 5 is constructed as follows: 7

The numeral 37 represents a horizontal cylindrical opening extendingthrough the upper part of the wall 13 from the replenishing chamber toone of. the working chambers and provided at its inner or rear end withan internal forwardly facing shoulder 38. Within the inner or rear partof this opening and engaging with the shoulder 38 is a perforated washeror abutment ring 39 of metal. In the central part of this opening andengaging with the front side of the washer 39 is a filter plug 40 ofcompressed felt or other fibrous material. In the front or outer part ofthis opening is arranged a cylindrical retaining plug 41 of metal whichengages its rear end with the filter plug and is held in place withinthe opening 37 by deforming or upsetting part of the front side of thewall 13 against the front end of the retaining plug, as shown at 42 inFigs. 1 and 3.

The corner at the inner end of the retaining plug is chamfered orbeveled as shown at 43 so as toform a collecting chamber 44 between thefilter plug and the retaining plug, and this collecting chamber isplaced in communication with the replenishing chamber by a longitudinalgroove 45 formed in the periphery of the retaining plug.

If desired the central part of the front end of the retaining plug maybe provided with 'two grooves 46 at right angles to each other,

' as shown in Fig. 6, or aplurality of grooves 47 which intersect eachother on the front end of the retaining plug, as shown in Fig. 7 so asto further increase the capacity of the collecting chamber between thefilter plug and the retaining plug and lead any liquid and air passingthrough the filter to the longitudinal groove 45.

If desired the washer 39 may be omitted in which case the filter plug isengaged directly with the shoulder 38, as shown in Fig.4.

As the pistons oscillate in the working chambers either during high orlow pressure strokes the pressure in the collecting chambers will at notime be less than in the replenishing chamber. This will'permit amovement of liquid with the entrained air or gas outward from theworking chambers through stroke against a return movement 0 the ventingdevices to thereplenishing chamberbut will not permitreturn movement ofair or gas back-from the replenishing chamber into the working chambers.'Any'liquid forced outwardly through the filter plug 76 gathers'in thecollecting chamber between the same and the retaining plug and isconducted by the vent passage to'the r'eplenishe ing chamber. i

The restricted cross vent passage compared with its length limits thetravel of theliquid and air through the same so that at no single strokeof the pistons will there be a movement of any part of the liquidcompletely through thevent passage. 5

Thervent passage will thus be at all times sealed by some "liquid of theprevious piston f the air and gas.

The fibers of the filter plug should be suffig;

ciently close so that the interstices between the fibers are of lessarea thanthe area of the vent passages inthe retaining plug. I By thismeans any dust, packing or other foreign material present in theresistance liquid will 6 be held back by the filterplugand preventedfrom clogging the: vent passage, thereby maintaining the venting meansinoperative condition and permitting the absorber to function mostefiiciently.

In the modified form- 0f this invention shown Fig. 8 two pockets 56 areformed in the upper part of the upper partition sec tion 18 whichpocketsare both connected with the upper part of the replenishing chamber by arestraining passage 57 formed in the; wall 13, short branch ventpassages 48 communicating with the pockets '56 and a col-.

lecting chamber 49 arranged between the long and short passages.- Eachpocket contains a 165 filter plug 50. The upper ends of both right andleft working chambers are thus vented into the replenishing chamber andair and liquid are permitted to pass from the working chambersthroughthe filterplugs and 11b vent passage to the replenishing chamber, butany dirt is caught by the filter and prevented from reaching the ventpassages and obstructing thesame:

'In this last-mentioned construction. some '115 of the liquid and air orgas will also be forced from the high pressure end'of one workingchamber-into the low pressure end of the other working chamber and apart of'the liquid and air orgas will flow backthrough the connectingpassage between these working chambers when the pressures are reverseddue f to'the oscillation of the pistons;

Instead of making the retaining plug cylindrical and'providing the samewith a longitudinal vent passage, this plug'inay be provided withanscrew'thread 51 which engages with'a screw-threaded opening 52 inv thewall 13, and the summit of one of these threads being removed, as shownin Fig.9, 1

sectional area of the 8 or thesum mi tsof both of these threads be ingpartly removed to form' a spiral vent passage between: the plug 41 andthe opening 1 in the wall 13 which receives thisplug. y I claim as myinvention i 1. A hydraulic'shock absorber having a working chamber whichis provided in one of its walls with a permanently open but restrictedvent. passage, and a filter between Qf-Sitld chamber and said passage.-

2.: A hydraulic shock absorber havinguav working chamber which isprovided in one I of its walls with a vent passage, a rigid retainingplug arranged in the outer part of igsaid passage" and having a groove,and a filter plug arranged in said passage andengaging the inner end ofsaid retainingv plug.

3. A hydraulic shock absorber having a v working chamber which isprovided in one of l its walls with a vent passage, a rigid retainingplug arranged in the outer part of said passage and provided on itsperiphery with a longitudinal groove and at its inner i edge-with achamfered edge, and a filter plug *:arranged in said passage andengaging the v inner end-of said retaining plug. r

4. A hydraulic shock absorber having a working chamber which isprovided. in one of its walls'with a ventpassage, a rigid retaining plugarranged in the outer part of said passage and provided on its peripherywith a longitudinal groove and at its inner edge with a chamfered edge,a filter'plug arranged in said passage and engaging the 3 inner end ofsaid retaining plug, and an abutment ring arranged in the inner part ofsaid passage and engaging with the inner end of said filter plug;

5. A hydraulic shock absorber having a V iworking chamber which isprovided-in one of its walls with a vent passage, a rigld'retaining plugarranged 1n the outer part of said passage and provided on its peripherywith a longitudinalgroove and at its inner Hedge'with a chanifcr'ededge, a filter plug arranged in said passage and engaging the inner endof said retaining plug,'and an abutment ring'arranged in the inner partof said passage and engaging with the inner end of said filter plugsaidwall provided with a shoulder engaging with the inner side of saidring and also with a deformation engaging with the outer end of saidretaining plug.

6. A hydraulic shock absorber having a working chamber provided with avent passage having a restricted section, and filter material in saidpassage in front of theinner end of said restricted section, saidpassage being always open to the flow of fluid.

V In testimony whereof 'I herebyaflix my signature.

RALPH; .F. PEO.

